This invention relates to fire-retardant insulating oils.
Recently, electric machineries and tools such as oil-filled transformers, condensers and the like have been required to be fire-retardant and small-sized, and silicone oil has been substituted for PCB which has heretofore been used. Further, mixtures of an aryl phosphate and a mineral oil type insulating oil have already been known as insulating oils which are more inexpensive and fire-retardant than silicone oil. However, the mineral oil type insulating oils are disadvantageous in that in general, they are poor in solubility in aryl phosphates.